Optical waveguide technology provides a solution to the continuing telecommunications challenge of capacity to transmit with precision high volumes of data. Current fiber optic systems transmit greater than to 1012 bits/sec.
Basically, commercial waveguide systems use optical fibers to carry large amounts of multiplexed digital data over long distances from a transmit terminal to a receive terminal. The maximum distance that the data can be transmitted in the fiber without amplification or regeneration is limited by the loss associated with the optical fiber and other components in the system. To transmit optical signals over long distances, optical fiber communication systems may include a number of amplifiers located along the fiber route from the transmit terminal to the receive terminal. Each amplifier optically boosts the weak signal to compensate for the transmission losses, or attenuation, which occurred subsequent to the last amplification. Most typical are rare earth doped optical fiber amplifiers.
The prior art teaches that an optical fiber doped with an appropriate substance can, when properly excited, radiate energy via stimulated emission at the same wavelength as the transmitted signal. Thus, such optical fiber acts as an amplifier. Light energy to excite the dopant is generated by an optical pump external to, yet optically connected to the optical fiber amplifier. Most frequently the pump device is connected to the optical fiber amplifier by means of an optical coupler. Effective connection requires sophisticated technology to ensure proper alignment of the optical fiber amplifier and the optical coupler as well as efficient energy transfer.